Blending LLDPE and Ground Rubber Tires

In this article, a set of blends was prepared from ground rubber tires (GRT) and linear low-density polyethylene (LLDPE). The effects of kneading time and functional polymers on the mechanical properties of the blends were investigated. It was found that the blend which contained styrene-butadiene-styrene (SBS) copolymer as functional polymer, with a kneading time of 20 minutes, behaved best with regard to mechanical properties, and that the utilization of GRT could reach as high as 61%. Atomic force microscopy (AFM) and differential scanning calorimetry (DSC) results showed that good adhesion between the particles and the surrounding LLDPE matrix was achieved in the blend.     

天然短纤维增强橡胶复合材料的研究进展

介绍了短纤维的预处理方法,总结了短纤维在橡胶中的混合、分散及取向状态,综述了短纤维-橡胶复合材料在轮胎、胶带和胶管中的应用进展,并提出了复合材料的研究方向.     

Synthesis and characterization of functionalized catechol-containing solution polymerized styrene-butadiene rubber

采用负离子聚合法,以四氢呋喃为极性调节剂,4-乙烯基儿茶酚缩丙酮为共聚单体,合成了苯乙烯质量分数为24%、1,2-结构质量分数为40%、4-乙烯基儿茶酚缩丙酮质量分数为5.8%~10.1%的溶聚丁苯橡胶;以3-乙烯基儿茶酚缩丙酮为共聚单体,合成了1,4-结构摩尔分数为80.7%~88.2%、3-乙烯基儿茶酚缩丙酮摩尔分数为2.6%~9.3%的溶聚丁苯橡胶。结果表明,采用负离子聚合法可以制备出含有邻苯二酚基团的溶聚丁苯橡胶。     

Comparison Properties of Natural Rubber (SMR L)/Ethylene Vinyl Acetate (EVA) Copolymer Blends and Epoxidized Natural Rubber (ENR-50)/Ethylene Vinyl Acetate (EVA) Copolymer Blends

Mixing torque, morphology, tensile properties and swelling studies of natural rubber/ethylene vinyl acetate copolymer blends were studied. Two series of unvulcanized blends, natural rubber/ethylene vinyl acetate (SMRL/EVA) copolymer blend and epoxidized natural rubber (50% epoxidation)/ethylene vinyl acetate (ENR-50/EVA) copolymer blend were prepared. Blends were prepared using a laboratory internal mixer, Haake Rheomix polydrive with rotor speed of 50 rpm at 120°C. Results indicated that mixing torque value and stabilization torque value in ENR-50 blends are lower than SMRL blends. The process efficiency of ENR-50/EVA blends is better due to less viscous nature of the blend compared to SMRL/EVA blends as indicated in stabilization torque graph. Tensile properties like tensile strength, M100 (modulus at 100% elongation) and E _b (elongation at break) increase with increasing EVA fraction in the blend. At the similar blend composition, ENR-50 blend shows better tensile properties than SMRL blends. In oil resistance test, swelling percentage increased with immersion time and rubber composition. At a similar immersion time, ENR-50 blends exhibit better oil resistance compared to SMRL blends. Scanning electron microscopy (SEM) of tensile fractured surface indicated that EVA/ENR-50 blends need higher energy to cause catastrophic failure compared to EVA/SMRL blends. In etched cryogenically fractured surface, size and distribution of holes due to extraction of rubber phase by methyl ethyl ketone (MEK) were studied and holes became bigger as rubber composition increased due to coalescence of rubber particle.     

CNT及Al2O3增强NR制备低生热高导热橡胶复合材料的工程化研究

橡胶材料的粘弹特性使其在周期性载荷下生热很大,而橡胶是热的不良导体,容易造成热积累,对于轮胎来说则容易产生热损伤。为了解决这一难题,风神轮胎股份有限公司与北京化工大学在国家973计划课题的支持下,对低生热高导热橡胶复合材料进行了工程化研究。首先通过进行小型密炼机混炼实验,与前期开炼机及对比胶相比,性能达到了制备轮胎要求,之后采用低温一次法炼胶技术进行了规模化生产,可以实现大规模连续化生产,制备的碳纳米管导热胶与企业对比胶相比导热率提高50%,并成功将导热胶加入到工程子午胎基部胶中,轮胎性能良好。     

Influence of rubber content in ABS in wide range on the mechanical properties and morphology of PC/ABS blends with different composition

A series of acrylonitrile–butadiene–styrene (ABS) with different rubber content were prepared by diluting ABS grafting copolymer containing 60% rubber with a styrene–acrylonitrile copolymer. ABS prepared were blended with bisphenol‐A‐polycarbonate (PC) at the ratio of 70/30, 50/50, and 30/70 to prepare PC/ABS blends. Influence of rubber content in ABS on the properties of ABS and PC/ABS blends were investigated. PC/ABS blends with different compositions got good toughness when the rubber in ABS increased to the level that ABS itself got good toughness. The tensile properties and processability of PC/ABS blends decreased with the increase of the total rubber content introduced into the blends. ABS with the rubber content of 30 wt% is most suitable to be used to prepare PC/ABS blends. The rubber content in ABS affected the viscosity of ABS, and subsequently the viscosity ratio of PC to ABS. As a result, the morphology of PC/ABS blends varied. The increase of rubber content in ABS results in finer structure of PC/ABS blends. POLYM. ENG. SCI. 46:1476–1484, 2006. © 2006 Society of Plastics Engineers.     

顺丁橡胶共混改性研究概况

顺丁橡胶(BR)以其良好的弹性、耐寒性、耐磨性和动态性能而广泛应用于轮胎等橡胶制品。采用共混方法,将BR和其它聚合物共混,产生具有某些特殊性能的新材料。本文介绍了顺丁橡胶(BR)在橡胶/橡胶共混、橡胶/树脂共混及复合材料方面的研究情况。     

Analysis of Membrane Reactors for Integrated Coupling of Oxidative and Thermal Dehydrogenation of Propane

This study presents strategies capable to intensify the thermal dehydrogenation of propane (TDH) using integrated reactor concepts. An inert packed bed membrane reactor for distributed dosing of oxygen to realize the oxidative dehydrogenation (ODH) was studied and compared to a reactor with catalytically active membrane. The latter concept allows to combine TDH and ODH in one apparatus to overcome the chemical equilibrium by in situ conversion of the by‐product H₂ using O₂ or in a reverse water‐gas shift reaction by CO₂. If CO₂ is used as active sweep gas the reactor offered better performance regarding yield and selectivity. Strategies for further thermal integration are discussed.     

工程轮胎胎面配方试验室耐切割性能试验

在试验室里对工程轮胎胎面胶配方的性能测试,长期以来都是采用常规的试验项目,如拉伸性能、抗撕裂性能和阿克隆磨耗等。但是,工程胎在矿山上使用的条件相当苛刻,特别是要求工程胎胎面胶料要具有良好的耐切割性能。文中使用RCC-1型橡胶动态切割试验机对胎面胶配方进行耐切割性能试验。试验数据表明,该项试验为配方设计者对胶料配方是否具有良好的耐切割性能提供了预期评估。通过轮胎的实际路面试验获悉,试验室的预期与实际试验结果有较好的相关性。     

Enhanced fracture toughness of epoxy resins with novel amine‐terminated poly(arylene ether sulfone)–carboxylic‐terminated butadiene‐acrylonitrile–poly(arylene ether sulfone) triblock copolymers

Amine‐terminated poly(arylene ether sulfone)–carboxylic‐terminated butadiene‐acrylonitrile–poly(arylene ether sulfone) (PES‐CTBN‐PES) triblock copolymers with controlled molecular weights of 15,000 (15K) or 20,000 (20K) g/mol were synthesized from amine‐terminated PES oligomer and commercial CTBN rubber (CTBN 1300x13). The copolymers were utilized to modify a diglycidyl ether of bisphenol A epoxy resin by varying the loading from 5 to 40 wt %. The epoxy resins were cured with 4,4′‐diaminodiphenylsulfone and subjected to tests for thermal properties, plane strain fracture toughness (K_IC), flexural properties, and solvent resistance measurements. The fracture surfaces were analyzed with SEM to elucidate the toughening mechanism. The properties of copolymer‐toughened epoxy resins were compared to those of samples modified by PES/CTBN blends, PES oligomer, or CTBN. The PES‐CTBN‐PES copolymer (20K) showed a K_IC of 2.33 MPa m^0.5 at 40 wt % loading while maintaining good flexural properties and chemical resistance. However, the epoxy resin modified with a CTBN/8K PES blend (2:1) exhibited lower K_IC (1.82 MPa m^0.5), lower flexural properties, and poorer thermal properties and solvent resistance compared to the 20K PES‐CTBN‐PES copolymer‐toughened samples. The high fracture toughness with the PES‐CTBN‐PES copolymer is believed to be due to the ductile fracture of the continuous PES‐rich phases, as well as the cavitation of the rubber‐rich phases. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1556–1565, 2002; DOI 10.1002/app.10390     

Interfacial adhesion evaluation in (low‐density polyethylene)/elastomer blends

Low‐density polyethylene (LDPE) with different elastomers at a ratio of 50/50 wt% blends was prepared by using a co‐rotating twin‐screw extruder. Three kinds of elastomers were used: ground tire rubber (GTR), partially crosslinked butyl rubber (Kalar^®), and styrene‐butadiene‐rubber block copolymer (SBS; Kraton^®). For better characterization of interaction between polyethylene and elastomer, influence of the type of elastomer on the properties of compositions LDPE/elastomer was determined. In the studies, two types of partially crosslinked butyl rubber (differing over filler content and Mooney viscosity) and two types of SBS (differing over structure: linear/branched) were used. The influence of kind and type of elastomer on static mechanical properties (tensile strength, elongation at break, hardness), dynamic mechanical properties, thermal properties, and morphology of obtained compositions were characterized. LDPE/linear SBS copolymer blend had the best mechanical properties, as a result of better compatibility in comparison with other investigated blends. The reason for improved compatibility was an increase of mobility of chain segments in the amorphous phase of polyethylene associated with their partial plasticization by flexible polybutadiene blocks present in SBS copolymer. J. VINYL ADDIT. TECHNOL., 22:492–500, 2016. © 2015 Society of Plastics Engineers     

轮胎橡胶复合材料的制备方法

环氧化天然橡胶是一种对天然橡胶进行环氧化改性得到的新型聚合物,具有优异的气密性、耐油性以及良好的黏着性,同时具有良好的抗湿滑性与较低的滚动阻力,在高性能绿色轮胎的应用中有广阔的应用前景。以环氧化天然橡胶复合材料为例,探究制备方法和过程。     

Thermal and mechanical properties of silicon rubber/cis‐polybutadiene rubber/ethylene–propylene–diene monomer blends

Considering the properties of silicon rubber, ethylene–propylene–diene monomer (EPDM), and cis‐polybutadiene rubber (BR), a blend made by a new method was proposed in this article; this blend had thermal resistance and good mechanical properties. The morphology of the blend was studied by SEM, and it was found that the adhesion between the phases of BR, EPDM, and polysiloxanes (silicon rubber) could be enhanced, and the compatibility and covulcanization were good. The influence of the mass ratio of peroxide and silica on the mechanical properties and thermal resistance of the blend was studied. The results showed that the mechanical properties and thermal resistance of the blend were improved when silicon rubber/BR/EPDM was 20/30/50, dicumyl peroxide/sulfur was 2.5/2.5, and the amount of silica was 80 phr. The integral properties of rubber blend had more advantages than did the three rubbers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4462–4467, 2006     

PS/SBR-g-PS共混物的力学性能和形态结构

采用种子乳液聚合技术在丁苯胶乳上接枝聚合苯乙烯 ,合成了一系列丁苯橡胶接枝聚苯乙烯共聚物 (SBR-g-PS)。将其与聚苯乙烯 (PS)树脂共混后 ,考察了 SBR-g-PS的组成 (SBR/ PS)对共混物的力学性能和形态结构的影响。结果发现 ,当 SBR/ PS为 6 7/ 33-5 0 / 5 0时 ,PS/ SBR-g-PS共混物表现出良好的综合力学性能 ,在 SBR-g-PS中随着接枝 PS的增多 ,像胶粒子在基体中的分散状况获得改善 ,在大橡胶颗粒中含有大量的 PS次级粒子。在外负载的作用下 ,共混物中的大橡胶颗粒引发了大量的银纹 ,吸收了断裂应变能 ,从而提高了材料的冲击韧性。     

The use of cryogenically ground rubber tires as a filler in polyolefin blends

The effects of cryogenically ground rubber tires (CGT) on some of the mechanical properties of blends with linear low density polyethylene (LLDPE) and high density polyethylene (HDPE) are presented. Precoating the CGT particles with an ethylene-acrylic acid copolymer is shown to overcome most of the deleterious effects of adding CGT to LLDPE, while still retaining composite processability. A blend of 40 wt% EAA coated CGT particles with LLDPE is shown to have impact and tensile strengths that are 90% of those for the pure LLDPE, representing increases of 60 and 20%, respectively, over blends with uncoated particles. Blends of LLDPE with ground tire bladders demonstrate that even better mechanical properties can be obtained with similar large rubber particle size but somewhat better adhesion. For HDPE, however, it is shown that with large rubber particles, moderate adhesion is not sufficient to produce useful composites.     

Development of high‐strength fibers from aliphatic polyketones by melt spinning and drawing

We have investigated the formation of high‐strength, high‐modulus fibers from four aliphatic polyketone resins. One resin was a perfectly alternating copolymer of ethylene and carbon monoxide, while the other three were terpolymers containing up to 6 mol % propylene. The mechanical properties were measured as a function of processing conditions, and the structures of the filaments were characterized using birefringence, WAXS, SAXS, SEM, and thermal analysis. Fibers formed from all resins develop very high molecular orientations and a microfibrillar structure. Fibers having room temperature tenacities as high as 10 gpd (～1.1 GPa) were obtained. Tensile moduli reached values as high as 120 gpd (～13 GPa). The melting point of the fibers was primarily dependent on the composition of the resin, while the maximum strength and modulus were largely determined by the maximum draw ratio achieved. The maximum draw ratio achieved in the present experiments was greater for the terpolymers than for the copolymer. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1794–1815, 2001     

溶聚丁苯橡胶2557-A在轮胎中的应用

按照纯炭黑配方,将溶聚丁苯橡胶(SSBR,牌号为2557-A)同乳聚丁苯橡胶(ESBR,牌号为1712)对比应用于全钢和半钢子午线轮胎胎冠胶配方中,确定了合适的胎冠胶配方,且进行了轮胎的试制和性能检测。结果表明,与ESBR 1712全钢胎冠胶相比,同等用量SSBR 2557-A的胎冠胶拉伸强度、定伸应力、Akron磨耗性能和压缩生热等性能均得到提高,但DIN磨耗性能有所下降,且具有更优的抗湿滑性和更低的滚动阻力;与ESBR 1712半钢胎冠胶相比,SSBR 2557-A胎冠胶具有优异的抗湿滑性能,而其他性能相差不大;采用SSBR 2557-A全钢子午线轮胎胎冠胶配方试制的轮胎顺利通过了耐久性试验;采用SSBR 2557-A半钢子午线轮胎胎冠胶配方试制轮胎的外缘尺寸、强度、脱圈阻力和高速性能、耐久性均达到国家标准,且还能够较大幅度提高轮胎的抗湿滑性能和滚动噪音性能。     

High-strength/high-modulus fibers of p-phenylene oxadiazole/n-methyl hydrazide copolymers—a new class of high-performance organic materials

p-Phenylene oxadiazole/N-methyl hydrazide copolymers were prepared by polymerization of terephthalic acid, dimethyl terephthalate, and hydrazine sulfate in fuming sulfuric acid, and coagulation of the polymer was obtained in aqueous sulfuric acid. Fibers spun from these copolymers have unusually high strength and modulus, making these materials attractive for the reinforcement of articles such as tires. Yarn tenacities of 16–21 gpd and moduli of 350–450 gpd were obtained. Yarn of these copolymers showed no significant degradation under conditions to which a tire cord material is subjected in tire building and end use. In their performance in vehicle tires, tire cords were found to be competitive with other reinforcing agents such as fiber glass, steel, and commercial poly(p-phenyleneterephthalamide).     

聚氨酯改性聚硅氧烷的制备与应用

以摩尔质量较大的端羟基聚二甲基硅氧烷（107硅橡胶）为软段、液化改性二苯基甲烷-4,4＇-二异氰酸酯为硬段,空气中的水分为交联剂制备了聚硅氧烷-聚氨酯（PDMS-PU）共聚物。采用傅里叶红外光谱仪（FTIR）对材料的结构进行分析,并测试了材料的固化性能、力学性能、水解性能以及耐油性能。结果表明,随着107硅橡胶含量的增加,PDMS-PU共聚物的拉伸强度先增后减,拉断伸长率逐渐下降;共聚物的力学性能随着固化时间的增加先增后减;经改性后,PDMS-PU的耐油性能大大提高了,随着107硅橡胶含量的增加,共聚物的耐油性明显下降。当107硅橡胶质量分数为80%,固化温度为20℃时,共聚物17 h后完全固化,固化后拉伸强度为0.8 MPa,拉断伸长率为75%,此时共聚物耐油性较好。     

TBIR改性NR硫化胶的研究

研究了两种牌号反式-1,4-丁二烯-异戊二烯共聚橡胶(TBIR)改性天然橡胶(NR),结果表明,10~50份TBIR与NR共混,并用胶焦烧时间(t10)和工艺正硫化时间(t90)略有延长。相比NR硫化胶,NR/TBIR并用硫化胶力学强度保持在较高范围,屈挠疲劳性能大幅度提高,其中NR/TBIR-20=50/50硫化胶一级屈挠疲劳寿命可提高28.6倍,六级屈挠疲劳寿命可提高11.9倍。DMA结果表明,NR与TBIR具有优异的相容性。RPA及DMA 结果均表明NR/TBIR并用硫化胶具有更低的滚动阻力。综合可知,TBIR是一种高性能的合成橡胶新材料,可显著改善NR的综合性能。